scrub typhus

Scrub typhus, also known as bush typhus, is a disease caused by a bacteria called ORIENTIA TSUTSUGAMUSHI.

Scrub typhus is spread to people through bites of infected chiggers (larval mites).

Most cases of scrub typhus occur in rural areas of Southeast Asia, Indonesia, China, Japan, India, and northern Australia. Anyone living in or travelling to areas where scrub typhus is found could get infected

Scrub typhus is not transmitted directly from person to person; it is only transmitted by the bites of vectors
Chiggers are abundant in locales with high relative humidity (60%–85%), low temperature (20°C–30°C), low incidence of sunlight, and a dense substrate-vegetative canopy.
Occupational risk is higher in farmers (aged 50–69 years), females.

1. SCRUB TYPHUS Pankaj S ingh R ana Nurse Practitioner in Critical C are

2. INTRODUCTION Scrub typhus, also known as bush typhus, is a disease caused by a bacteria called  ORIENTIA TSUTSUGAMUSHI . Scrub typhus is spread to people through bites of infected chiggers (larval mites). Most cases of scrub typhus occur in rural areas of Southeast Asia, Indonesia, China, Japan, India, and northern Australia. Anyone living in or travelling to areas where scrub typhus is found could get infected As per CDC

3. Scrub typhus is not transmitted directly from person to person; it is only transmitted by the bites of vectors Chiggers are abundant in locales with high relative humidity (60%–85%), low temperature (20°C–30°C), low incidence of sunlight, and a dense substrate-vegetative canopy. Occupational risk is higher in farmers (aged 50–69 years), females.

4. TRANSMISION

5. SIGN AND SYMPTOMS Fever and chills Headache Body aches and muscle pain A dark, scab-like region at the site of the chigger bite (also known as eschar ) Mental changes, ranging from confusion to coma Enlarged lymph nodes Rash

6. More virulent strains of  O. tsutsugamushi  can cause  hemorrhaging  and  intravascular coagulation . Morbilliform rash,   splenomegaly  are typical signs . Leukopenia  and abnormal liver function tests are commonly seen in the early phase of the illness .  Pneumonitis ,  encephalitis , and  myocarditis  occur in the late phase of illness. It has particularly been shown to be the most common cause of  acute encephalitis syndrome  in Bihar, India

7. DIGNOSTIC EVALUATION   eschar incidence varies from 7% to 97% in endemic areas and is painless.  Eschars are often found in covered areas of the body, such as the groin, axilla , chest, and lower back, including the buttocks

8. DIGNOSTIC EVALUATION The gold standard is  indirect immunofluorescence C ulture and  polymerase chain reaction The cheapest and most easily available serological test is the  Weil-Felix test . (non reliable) ELISA ( enzyme-linked immunosorbent assay)

9. Routine laboratory studies in patients with scrub typhus reveal early lymphopenia with late lymphocytosis . A decrease in the CD4:CD8 lymphocyte ratio may also be noted. Thrombocytopenia is also seen. ] The hematologic manifestations may raise the suspicion of dengue infection.   Elevated transaminase levels may be present in 75-95% of patients. Hypoalbuminemia occurs in about 50% of cases, whereas hyperbilirubinemia is rare.

10. This illness is thus clinically indistinguishable from malaria, dengue fever, other rickettsioses , leptospirosis , and enteric fever, which are common causes of acute undifferentiated fever as seen in scrub typhus.

11. TREATMENT

12. As per DHR-ICMR guidelines for diagnosis and management of rickettsial diseases in India (2015), the scrub typhus can be managed at different levels of health care facility as – When rickettsial disease is suspected, without waiting for laboratory confirmation, antibiotics should be started.  Without treatment, the disease is often fatal. Since the use of antibiotics, case fatalities have decreased from 4–40% to less than 2%. 1 .       At primary level health care facility: The health care providers should: a )        Recognize disease severity : In the patients with complications, Doxycycline should be started before referral.

13. b ) Refer to secondary or tertiary level health care facility  in patients with complications like ARDS, meningo -encephalitis, acute renal failure and multi-organ dysfunction. Along with recommended management of community acquired pneumonia, start Doxycycline when the scrub typhus is considered likely. c ) In case of fever for 5 days or more where dengue, malaria and typhoid have been ruled out; following drugs should be administered when scrub typhus is considered likely –

14. For Adults: a) Doxycycline -200 mg/day in  two divided doses ×7 days ( for  patients ˃45 kg ). Advise the patients to swallow capsules with plenty of fluid during meals while sitting or standing    OR b ) Azithromycin-500 mg in a single oral dose × 5 days.

15. For Children: a) Doxycycline -4.5 mg/kg of body weight/day in two divided doses (for children < 45 kg)   Or b) Azithromycin-10mg/kg body weight in a single dose  × 5 days.   For Pregnant women: Azithromycin can be administered to pregnant women, as doxycycline is contraindicated. Azithromycin - 500 mg in a single dose × 5 days.  

16. 2. at secondary and tertiary level health care facility : a) Uncomplicated cases: Start the treatment as specified in above cases.   b)       In complicated cases: start the treatment as following- i )        Intravenous Doxycycline : 100mg twice daily in 100 ml of Normal Saline to be infused over ½ an hour initially followed by oral therapy × 7-15 days.   OR                        

17. ii)      Intravenous Azithromycin : 500mg IV in 250 ml Normal Saline to be infused over 1 hour O.D. × 1-2 days followed by oral therapy × 5 days. OR iii)    Intravenous Chloramphenicol : 50-100 mg/kg/day 6 hourly to be infused over 1 hour initially followed by oral therapy × 7-15 days . iv)  Management of complications should be done as per institutional protocols. Doxycycline and/or Chloramphenicol resistant strains are sensitive to Azithromycin .

18. Prophylactic Treatment: Prophylaxis is recommended under special circumstances in certain areas where the disease is endemic. For prophylaxis, a single oral dose of Chloramphenicol or tetracycline is given once in every 5 days for a total of 35 days, with 5-day non-treatment intervals. It produces active immunity to scrub typhus.

19. CONCLUSION Scrub typhus is an important cause of febrile illness in the Asia-Pacific region. The main management challenge is institution of specific therapy in a timely and an effective manner. For this, rapid and accurate diagnosis becomes necessary, especially in the absence of eschars . In resource-poor endemic settings, clinical prediction rules have been defined and found useful Finally, appropriate treatment should be initiated, keeping in mind the risk and benefits afforded by such treatment.